DESCRIPTION: (Applicant's Abstract) The overall objective of this application is to develop a clinically relevant vaccine strategy for the treatment of minimal residual metastatic cancer. The specific focus of this application is to optimize a novel technique for antigen loading of dendritic cells (DC), RNA transfection. The applicant proposes to first define the role of RNA transfected DC in inducing cytotoxic T lymphocytes (CTL) using a defined antigen, then exploit the potential application of total tumor RNA as a source of authentic tumor rejection antigens. He is currently conducting a phase I clinical trial of active immunotherapy using DCs transfected with RNA encoding a tumor associated antigen overexpressed on over 90% of colorectal carcinomas, carcinoembryonic antigen (CEA). He proposes to test the hypothesis that CEA RNA transfected DC will elicit a measurable CEA specific CTL response in the treated patients. In addition, he proposes to test the hypothesis that various modifications of RNA will enhance the ability of the DC to present antigen to CTL. He hypothesizes that the magnitude and clinical relevance of a CEA specific CTL response will be optimal in a setting of minimal tumor burden, therefore, he will test this hypothesis in a phase II clinical trial of active immunotherapy using CEA RNA transfected DC in patients following "curative" resection of colorectal cancer metastasis. Once he has defined the magnitude and clinical effect of CEA RNA transfected DC, he proposes to exploit a major advantage of using tumor antigen in the form of RNA to overcome a serious concern of cancer immunotherapy, i.e., directing immunity against authentic tumor antigens. He hypothesizes that since the transfection of exquisitely small quantities of RNA encoding for antigen into DCs are sufficient to elicit CTL responses, he can use RNA isolated directly form tumors, which contain the entire repertoire of tumor antigens, to transfect DCs. He hypothesizes that colorectal tumor RNA transfected DCs will be potent in stimulating a T cell response against CEA and many, if not all, other antigens expressed by the tumor. He proposes to develop methods to isolate total tumor RNA from CEA overexpressing colorectal cancers and perform a phase I clinical trial of total colorectal tumor RNA transfected DC. These Specific Aims reflect a logical progression of studies necessary to determine the role of RNA transfected DC as a widely applicable platform for presenting defined and/or undefined tumor rejection antigens to elicit tumor specific immunity.